Inventory and abundance of mealybug species in immature and mature cocoa farms in Côte d'Ivoire

Abstract

From 2013 to 2018, surveys were conducted in counties not previously surveyed in order to determine species of mealybugs present in the cocoa orchard in Côte d'Ivoire as well as their abundance according to the age of cocoa trees. Immature and mature cocoa trees were inspected to hand‐height in 5 and 29 counties infected with Cacao swollen shoot virus (CSSV). In each cocoa farm, mealybugs were searched for on fruits, leaves, flowers, twigs and trunks. Mealybug species were identified, and colonies were counted. Five mealybug species were identified on immature cocoa trees: Ferrisia virgata, Formicococcus njalensis, Planococcus citri, Planococcus kenyae and Pseudococcus longispinus. In addition to these species, four species, Dysmicoccus brevipes, Maconellicoccus hirsutus, Phenacoccus hargreavesi and Pseudococcus jackbeardsleyi were identified on mature cocoa trees. On immature cocoa trees, Fo. Njalensis, Pl. citri and Ps. longispinus comprised were, respectively, 35%, 33% and 19% of colonies, respectively. On mature cocoa trees, Fo. Njalensis and Pl. citri comprised 63.2% and 21.0%, and others species 15.8%. Nevertheless, the abundance of mealybug species varied according to the age of cocoa trees. The preferred organs of mealybugs were pods (74.1%) followed by twigs (13.4%) and flowers (7.4%). Previously, the mealybug Paracoccus burnerae (Brain) was found on Theobroma cacao, which is the first record for this species in Côte d'Ivoire and on this host‐plant.

Mealybug (Hemiptera: Pseudococcidae) Species Associated with Cacao Mild Mosaic Virus and Evidence of Virus Acquisition

“…These species have been reported to affect cacao in Africa, the Caribbean, and South America [37][38][39], but this is the first report of them affecting cacao in Florida. Neither species has been tested for their ability to transmit viruses to cacao, but they are closely related to confirmed vectors, and have been detected on CSSV-infected cacao in Cote d'Ivoire [39]. Most research on mealybugs affecting T. cacao is done in West Africa, where the more damaging, and economically significant, viruses are found.…”

Molecular Identification of Mealybug Species (Hemiptera: Pseudococcidae) Affecting <em>Theobroma cacao</em> for Improved Pest Management

“…Both P. jackbeardsleyi and M. hirsutus, have been reported affecting cacao in Africa and the Americas [19,20]. Neither has been tested for their ability to transmit viruses to cacao, but they are closely related to confirmed vectors, and have been detected on CSSV-infected cacao in Cote d'Ivoire [19].…”

“…Due to the high diversity of Pseudococcidae, each region has different species composition, and morphological differentiation of closely related species is challenging for non-specialists. On cacao, mealybug populations are composed of multiple species [4,7,8]. In West Africa, Pseudococcus njalensis (Laing) is the main vector, due to its abundance in the area [9], while Planococcus citri (Risso) is the most significant vector of cacao virus in Trinidad [4].…”

Effect of Proper Management of Cocoa Plants on the Occurrence of Swollen Shoot Disease in Kipiri - Côte d'Ivoire

“…This progression could be linked to the failure to manage the disease on a national scale. Indeed, methods of uprooting infected trees are difficult for producers to adopt because they destroy larges areas of cocoa trees [1][2][3][4][5][6].…”

“…Ivorian agriculture is dominated by cocoa cultivation, which is the main agricultural activity of the country [1]. Cocoa production in Cote d'Ivoire is about 1.50 million tons / year of cocoa beans, making country the first producer in the world with 35.6% of market share provides significant economic support Côte d'Ivoire state with 15% of the Gross Domestic Progress (GDP) and 30% of export earnings However, cocoa growing in Côte d 'Ivoire is increasingly facing various constraints, such as the aging of cocoa plots, the instability of cocoa buying prices, the attacks of mirids, black pod disease and especially Swollen shoot disease [4]. Indeed, since year 2003, the Swollen shoot 160 is a sentinel site of 10 Km × 10 Km.…”